Differential diagnosis of suboptimal oxygenator performance

Fried, David W; Zombolas, Theodore L; Wilgus, Michael; Mohamed, Hasratt; Mattioni, Gabriel J.

doi:10.1177/026765919300800607

Cited by 4 publications

(3 citation statements)

References 4 publications

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“…There are several published studies in the recent literature, some of these develop formulae that can be used as a tool to compare the different aspects of oxygenation and heat exchanger performance for a series of oxygenators, [3][4][5][6] or as a reference tool to test a single device for suboptimal functioning. [7][8][9][10] This study is designed to evaluate the performance characteristics of nine different types of hollow-fibre oxygenators in the clinical setting. We focused on oxygenation characteristics, heat exchanger performance, oxygenator pressure drop and blood trauma.…”

Section: Introductionmentioning

confidence: 99%

Clinical evaluation of nine hollow-fibre membrane oxygenators

et al. 2001

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In a comparative study we investigated the performance characteristics of nine hollow-fibre oxygenators. In a clinical setting, 10 units of each type of oxygenator were tested for oxygen exchange, transoxygenator pressure drop, heat exchanger performance and blood trauma. The oxygenators included are Maxima PRF Plus, Affinity, Forte, Affinity NT, Quantum, Optima, Capiox 1.8, Hilite and Quadrox. Ninety patients scheduled for elective coronary bypass surgery were enrolled in the study. Cardiotomy suction blood was not allowed to mix with the circulating blood. Samples were taken preoperatively (t1), immediately after cooling and crossclamping of the aorta (t2), during rewarming (t3), and postoperatively (t4). The results showed that under clinical conditions all of the tested oxygenators are well capable of meeting the normal and above-normal oxygen needs. The Quantum and Affinity NT are the best performing oxygenators with respect to oxygen transfer. The Quantum oxygenator with a small membrane surface area of 1.9 m2 has also the highest oxygen transfer per square metre. A direct relationship between shunt fraction and blood flow could not be established in all oxygenators. The lowest shunt fraction at 4 litres blood flow was seen in the Maxima, Quantum and Affinity NT groups (15%). At near physiological PaO2-values, we noticed a negative influence on the shunt fraction. Large differences exist in pressure drop between the oxygenators under standardized conditions with circulating priming, as well as during bypass. The lowest pressure drop was noticed in the Quadrox and Affinity NT, the highest in the Quantum, Capiox and Optima. However, we did not measure any differences in pressure drop after cooling and during re-warming. Differences exist between the heat exchanger performances. The Quadrox oxygenator is the most efficient, while the Maxima has the smallest performance factor. It was not possible to calculate heat exchanger performance for the Hilite due to incorrect temperature measurement. The high pressure gradients in some of the devices did not result in higher haemolysis. Plasma free haemoglobin values were low in each oxygenator. There are no differences in platelet drop postoperatively. The influence on blood trauma of the higher pressure drop in some of the tested devices, in combination with the higher centrifugal pump revolutions needed to overcome this gradient, has to be studied with longer perfusion times.

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Section: Introductionmentioning

confidence: 99%

Clinical evaluation of nine hollow-fibre membrane oxygenators

et al. 2001

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“…[2][3][4][5] The shunt fraction represents the percentage of venous blood which flows through the oxygenator without participating in effective gas exchange. Utilizing this technique, we were able to establish 'normal' or predicted shunt values for several different membrane oxygenators.…”

Section: Introductionmentioning

confidence: 99%

The proposed use of a 'screening test' to assess oxygenator performance

1993

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This study aimed to assess whether the use of the physiological shunt equation could (within the first five minutes of initiating CPB) serve as a 'screen' to differentiate normal and dysfunctional oxygenator performance. If dysfunction severe enough to require replacement was necessary, the normothermic patient could be weaned from CPB and replacement would be carried out under safe, controlled conditions. This technique would require postponing the induction of hypothermia (if used), aortic cross-clamping, and arresting the heart until after this screen was completed. This study demonstrates that a strong negative correlation exists between the degree of blood shunting and the membrane's 0 2 transfer performance (r = -0.874). This relation enables us to predict 0 2 transfer performance when only the shunt fraction is known. Of the 41 oxygenators used in this study, 40 demonstrated normal, or below-normal, shunt fractions. Oxygen transfer performance at or above predicted levels would be anticipated for these oxygenators. One of the 41 oxygenators had mildly elevated shunt fractions, which we predicted would be associated with mild 0 2 transfer dysfunction. Based on the performance screen worksheet we created, replacement was not necessary since the oxygenator maintained high levels of 0 2 transfer in reserve despite its marginal performance dysfunction. Assessment of oxygenator performance dysfunction in this earliest phase of CPB would greatly reduce the incidence of emergency oxygenator replacement secondary to actual or perceived oxygenator failure later in the course of the procedure.

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“…. differentiate between (1) a normal oxygenator with reserve transfer: (2) a normal oxygenator without reserve; and (3) a failing or suboptimally performing oxygenator"(6).Devices that can provide automated, continuous oxygen consumption monitoring during cardiopulmonary bypass are long overdue. The CDI Blood Parameter Monitoring System 500 offers the clinician an additional tool in the effort to make cardiopulmonary bypass safer for the open-heart patient.…”

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confidence: 99%

CDI Blood Parameter Monitoring System 500—A New Tool for the Clinical Perfusionist

Fried

Leo

Mattioni

et al. 2000

J Extra Corpor Technol

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Sarns/3M Health Care has recently introduced the CDI 500 Blood Parameter Monitoring System. In addition to parameters previously available, this system now offers continuous monitoring of the patient’s oxygen consumption (VO2/min) and potassium concentration ([K+]). The purpose of this study was: (1) to compare the [K+] from the CDI 500 with the [K+] derived from our hospital’s laboratory; and (2) to compare the VO2/min from the CDI 500 with the results obtained utilizing the “gold-standard” Fick equation. The mean absolute difference in [K+] was 0.10 mEq/L with a mean percentage error of only 3.93%. The mean absolute difference in VO2/min was 18.78 ml O2/min, with a mean percentage error of 11.63%. We concluded that the [K+] correlated well and that 9.13% of the oxygen consumption percentage error was attributable to the exclusion of dissolved oxygen in the calculation used by the CDI 500, with the remaining 2.5% attributable to differences in technology. We recommended that future upgrades to the CDI 500 should include dissolved O2 when measuring oxygen consumption and consideration should be given to increasing the operating range for [K+].

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Differential diagnosis of suboptimal oxygenator performance

Cited by 4 publications

References 4 publications

Clinical evaluation of nine hollow-fibre membrane oxygenators

Clinical evaluation of nine hollow-fibre membrane oxygenators

The proposed use of a 'screening test' to assess oxygenator performance

CDI Blood Parameter Monitoring System 500—A New Tool for the Clinical Perfusionist

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